Add a `SettlementRepository.remove(id)` method for administrative purge/test cleanup

[Jagadeeshftw]

📌 Description

AnchorRepository and LiquidityRepository both expose a remove, but SettlementRepository only has create/save — there's no way to delete a settlement record outright. This is fine for normal lifecycle operations (which use cancel, not deletion), but there's no supported path for, e.g., purging test fixtures or correcting an erroneously-created settlement record without restarting the process.

🧩 Requirements and context

• Add remove(id: number): boolean to SettlementRepository, matching the return-true-if-existed convention already used by AnchorRepository.remove/LiquidityRepository.remove.
• This is a repository-layer primitive only — do not wire it to a public route in this issue unless it's clearly gated as an administrative operation; if adding a route, require the configured API key and note the destructive nature in the endpoint's summary.

🛠️ Suggested execution

• Add remove to src/repositories/settlementRepository.ts.
• Add tests in src/repositories/settlementRepository.test.ts covering removal of an existing id, a non-existent id, and that count()/all() reflect the removal.
• If a route is added, gate it behind apiKeyAuth (already true for all mutating routes when configured) and document the destructive/administrative nature explicitly in openapi.ts.

✅ Acceptance criteria

• SettlementRepository.remove(id) removes the settlement and returns true; returns false for an unknown id.
• count() and all() correctly reflect removal.
• New tests pass.

🔒 Security notes

A destructive delete on financial-adjacent settlement records; if exposed via a route, it must not be reachable without the same protections as other mutating endpoints, and ideally requires an explicit acknowledgement that it bypasses the normal cancel/execute lifecycle.

📋 Guidelines

• Minimum 95% test coverage
• Clear documentation
• Timeframe: 96 hours

[Agencybuilds]

Would love to work on this issue will produce an excellent result

[grantfox-oss]

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Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #163)
2. Your PR will be reviewed by the AnchorNet-Org maintainers

Good luck! Track your progress on GrantFox.

[Jagadeeshftw]

You're assigned! Go ahead and open a PR whenever it's ready, and reference this issue in the description (e.g. Closes #163) so it links up automatically.

If you have questions along the way, feel free to ask here. There's also a community chat if you want to hang out with other contributors: t.me/+vTbe0hOUKrFhNTJl